This invention relates to an improvement in a type of air heaters which provides a continuous flow of hot air by forcing unheated air to circulate through a series of interconnected, heated pipes. These heaters are frequently used in fireplaces, where the pipes are heated by a small fire and are quite useful in that they provide an economical source of hot air heat which can be used to heat rooms. These air heaters are generally not kept in the fireplace but are usually stored when not in use.
There are several types of prior art heaters. These prior art units are of one piece and are of considerable size. Further, since the pipes are made of a heavy gauge steel to withstand the heat from the fire, the prior art devices are also of considerable weight. Consequently, due to their substantial size, weight and unitary construction, the prior art heaters are difficult to transport, handle and store. In addition, their large size and pipe structure make them very unsightly.
Another more important drawback with the prior art heaters is that they are not efficient as there is a considerable amount of heat loss in the system. The prior art heaters are unprotected from cold air drafts which can cool the piping thereby cooling the air inside and reducing the ultimate temperature of the heated air expelled from the device. Furthermore, a large amount of the piping in some of the prior art devices extends away from the fire so that there is a considerable distance between these pipes and the fire. This necessarily reduces the heating effect on this piping and thereby also reduces the heating performance of the prior art heating unit. Finally, most prior art heaters are not arranged to allow the fireplace to be used for cooking when they are in operation.
Despite these drawbacks in terms of efficiency, handling and use, these types of heating units are becoming increasingly well-known and widely used because of the increasing cost of fuel oil, gas and electricity. Although they do not function as a complete subsitute for the other more expensive types of heating systems, they do supplement such systems at considerable savings since these units can operate by burning otherwise useless rubbish, such as newspapers, wrapping paper and wood chips. Therefore, in addition to providing an alternate source of heat thereby saving more precious fuels, these devices also serve to reduce the amount of waste material which must be discarded.